Browsing by Author "Kuo, Yue"

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Mechanism of a-IGZO TFT device deterioration-illumination light wavelength and substrate temperature effects
(2017-10-25)
Chen, Te-Chih
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Kuo, Yue
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Chang, Ting-Chang
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Chen, Min-Chen
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Chen, Hua-Mao
Device characteristics changes in an a-IGZO thin film transistor under light illumination and at raised temperature have been investigated. Light exposure causes a large leakage current, which is more obvious with an increase in the illumination energy, power and the temperature. The increase in the leakage current is due to the trap assisted photon excitation process that generates electron-hole pairs and the mechanism is enhanced with the additional thermal energy. The leakage current comes from the source side because holes generated in the process drift to the source side and therefore lower the barrier height. The above mechanism has been further verified with experiments of drain bias induced shifts in the threshold voltage and the subthreshold slope.
Stability of double gate amorphous In-Ga-Zn-O thin-film transistors with various top gate designs
(2017-12-01)
Chen, Te-Chih
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Kuo, Yue
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Chang, Ting-Chang
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Chen, Min-Chen
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Chen, Hua-Mao
Electrical characteristics of the dual-gate amorphous indium gallium zinc oxide thin-film transistors have been studied. Compared with the traditional bottom gate thin film transistor, the dual-gate structure has a larger on-current and a smaller threshold voltage shift because of the formation of an additional carrier channel and the depletion of the semiconductor layer. The top gate-to-channel barrier height is critical to threshold voltage and the stability of the thin film transistor. The complete overlap between the top gate and the channel region is important for the top channel function, which warrants the large on-current and low threshold slope shift. Therefore, the top gate design is critical to the performance and stability of the dual-gate thin film transistor. (C) 2017 The Japan Society of Applied Physics
Thin Film Transistors As Driving Devices for Attached Devices
(2014-01-01)
Kuo, Yue
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Chang, Geng Wei
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光電工程學系
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Department of Photonics
TFTs can be used as driving or detecting devices for purposes of optical, chemical, or biological sensing, imaging, displays, etc. Assuming the stability is not an issue, the poly-Si, IGZO, and a-Si:H TFTs were compared with respect to the device driving capability. For the drain-attached device, the maximum available power is determined by the device\'s resistance and the TFT\'s on-current. For the gate-attached device, the study is based on connecting a resistor and a capacitor in parallel. The raise or decay of the drain current is dependent on the RC time delay. Although the high mobility TFT has many advnatages, the low mobility TFT is adequate for certain applications. In real applications, the manufactuability and cost are important factors in choosing the TFT.